[R] Mean Help

[Jessica Streicher]

please provide a bit of the dataframe in the future using the dput() function

> x<-data.frame(height=1:10, color=sample(c("blue","green","brown"),10,replace=T))
> x
   height color
1       1  blue
2       2 green
3       3  blue
4       4 brown
5       5  blue
6       6 brown
7       7 green
8       8 brown
9       9 green
10     10 brown

> blue.eyes <- x[x$color=="blue", ]
> blue.eyes
  height color
1      1  blue
3      3  blue
5      5  blue

should create a new dataframe with only those that have blue eyes, then

> mean(blue.eyes$height)
[1] 3

should provide you with the mean of those.

On 31.10.2012, at 14:18, Hard Core wrote:

> I have a dataframe.
> Let's suppose that i have two columns. The first one contains height, the
> second one contains eye color that can be Green, Blue or Brown.
> I want to calculate the aritmetic mean of the height only for those people
> who have Blue eyes. How can I do it?
> Thank you for your availability.
> 
> 
> 
> 
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